This invention generally relates to a parallelogram suspension assembly for a vehicle, and more specifically to one having a brake component port through the axle seat. The suspension of this invention is particularly directed to one of a unitized structure wherein all of the operational components of the suspension, including brake components, are provided within the assembly itself. Thus, each of the suspension assemblies of this invention is self-contained, or unitized, such that the entire parallelogram arrangement may be included therewith.
Parallelogram suspensions are known in the art, as are such suspensions which also utilize air springs located rearward of a depending hanger and mounted between an axle seat or beam or the like and the chassis for resiliently supporting the chassis on the axle. Such a suspension is shown in U.S. Pat. No. 4,181,323 to Raidel. Prior to the Raidel patent, such suspensions had not been “unitized” in the sense that all of the operational components of the suspension are contained within each such suspension. The Raidel patent resolved many of the problems with prior art parallelogram suspensions by providing a unitized parallelogram air spring suspension wherein all of the operation components were provided with the suspension and mounted at the end of the axle for easy access and installation while maintaining a compact design resulting in preferred clearance of suspension components and limiting overall suspension weight.
In the parallelogram arrangement of prior art suspensions of this general type, including the Raidel suspension, it has been customary to suspend brake components from a surface of the suspension which significantly reduces overall suspension clearance and affects overall dynamics of suspension operation. Generally, to install the suspensions of this type is was preferable to attach brake cylinders and lines either below the suspension arm or inboard of the suspension arm. It is believed that the parallelogram arrangement of the prior art resulted from problems of space limitations in providing a unitized parallelogram arrangement and brake component location which problems have not heretofore been solved.
The Inventor has solved the problems inherent in brake component placement on parallelogram suspension arms by providing a brake port through the arm between the air springs and adjacent the axle. A brake cylinder, or other brake components, is mounted to the axle, the wheel or at other conventional attachment locations. The brake port is provided at a specific location transversely through the axle seat, substantially adjacent the axle. Generally, the brake components cannot be attached directly to the suspension unit. However, the orientation of the brake port through the axle seat adjacent the axle allows the brake components to project through the port without contacting the periphery of that opening. By placing brake components, such as lines and brake cylinders substantially within the suspension arm itself, spring clearance and ground clearance are maximized.
Generally, the suspension of this invention includes a hanger depending from the vehicle chassis to which the forward ends of at least two vertically spaced torque rods are pivotally mounted. A vehicle axle is rigidly secured to an axle seat having a portion extending forwardly of the axle seat but located rearward of the hanger and a portion extending rearward of the axle seat. Air springs are located rearward of the hanger and mounted between the chassis and the forward and rearward extensions of the axle seat for resiliently resisting axle movement upon loading and unloading of the axle.
The forward portion of the axle seat defines a pocket in which the rearward ends of the torque rods are pivotally mounted, the upper torque rod being offset downwardly to provide clearance from the axle seat. The entire parallelogram arrangement, including fasteners and openings for brake components is unitized as a single assembly along with the other operational components of the suspension while still providing compactness in design.
At least one of the torque rods may be mounted directly to the axle rather than the axle seat. In such an embodiment, it is preferred that at least one torque rod is attached at its forward end to the hanger bracket or chassis and at its rearward end to a bracket mounted to the axle inboard the suspension. In another embodiment, two or more torque rods may be attached to a bracket on the axle rather than to the suspension.
The rearward extension of the axle seat defines a compartment for housing various brake components it is preferable, however, to provide a brake port transversely through the sides of the axle seat so that the brake cylinder, or similar component, can be positioned substantially within the confines of the axle seat but remain accessible for service and replacement. This orientation of the brake components within the port attributes to suspension compactness with full utilization of space. Brake lines and similar component may be fit into the brake port itself or within the compartment(s) of the axle seat. Notches or similar openings may be provided in the periphery of the brake port to accommodate brake lines or brake components.
In this way, the unitized suspension assembly of this invention is particularly unique in its integration and orientation of a brake port within the axle seat structure of a parallelogram suspension.